1. Field of the Invention
The present invention relates to threaded couplings for use in connecting together elongate tubular members, such as tubing and casing joints, and, more specifically, to such a coupling on which can be mounted a control line such as a conduit for conveying fluids, electrical wires, cables, or the like.
2. Description of the Prior Art
In many downhole operations in oil and gas wells, there is a need to operate, control, or monitor equipment located in a borehole in which is disposed a string of tubular members, such as a string of tubing or casing. As is well known to those skilled in the art, to form a string of casing or tubing, successive sections or joints of tubing or casing are connected to one another by means of a coupling, the respective ends of the tubing or casing joints forming an externally threaded, pin connection, the coupling forming an internally threaded box connection at each end thereof. When it is necessary to operate, control, or monitor a piece of equipment to be located in the borehole, it is common practice to run the tubing or casing string together with one or more control lines disposed externally of the tubing or casing string. Currently, there is no accepted method of securing the control line to the tubing or casing string along its length, albeit that it may be connected at some point to the tubing or casing string as an adjunct to connecting it to the piece of downhole equipment to which it is attached.
It would therefore be of great benefit to have an assembly that would permit the control line(s) to be attached to the tubing or casing string (hereinafter xe2x80x9ctubular stringxe2x80x9d) at each coupling, thereby minimizing the possibility that the control line will become tangled or stuck in the borehole.
It is therefore an object of the present invention to provide a coupling for connecting tubular members, such as tubing or casing joints, to form a tubular string, the coupling being constructed to externally receive and hold a control line running along the tubular string.
Another object of the present invention is to provide a control line-tubular string assembly wherein the control line can be fastened to the tubular string along its length.
The above and other objects of the present invention will become apparent from the drawings, the description given herein, and the appended claims.
In one embodiment of the present invention, there is provided a novel coupling for connecting first and second tubular members. The coupling comprises a tubular body, the tubular body having a first end portion and a second end portion, a first, internally threaded box being formed in the first end portion and a second, internally threaded box being formed in the second end portion. The tubular body defines an outer, annularly extending surface, and at least one groove is formed in the outer surface and extends from the first end portion to the second end portion of the tubular body.
In another embodiment of the present invention, there is provided a tubular string and control line assembly comprising a coupling as described above, a first tubular member having a threaded pin end threadedly received in one end of the coupling and a second tubular member having a threaded pin end threadedly received in the other end of the coupling. A control lines is nested in the groove and extends along the tubular string. A tie holds the control line in the groove in the coupling.